Modular vascular catheter

ABSTRACT

A catheter is provided that comprises at least one proximal tubular module and a distal tubular module, each of the tubular modules having at least one section with spiral cuts, each pair of adjacent tubular modules are coupled by a joint, the joint comprising, (a) at least one snap-fit connector on a first tubular module and a snap-fit acceptor positioned on the adjacent tubular module, the snap-fit connector being elastically deformable when engaged, and (b) at least one stabilizing element, including, a tongue element positioned on the first tubular module or the adjacent tubular module, and a groove element positioned on the opposite, first tubular module or the opposite, adjacent tubular module.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/726,024, filed Oct. 5, 2017, which claims the benefit of and priorityto U.S. Provisional Application No. 62/404,552, filed Oct. 5, 2016.

BACKGROUND

Currently, there are a large number of different vascular catheters andmicrocatheters, each designed to enable access to different anatomicallocations in the vasculature. A key issue that catheter design faces iscontrolling pushability and flexibility across the length of thecatheter. Controlling pushability and flexibility is important in orderto enable the physician to negotiate access through various complex andoften tortuous, anatomical vasculature which is often found in thecardiovascular or neurovascular systems. One approach to modulatingflexibility is to form the catheter body from different types ofmaterials, e.g., stainless steel and or polymers, each of which hasdifferent functional properties. These materials may be combined into atubular construction via a coiled or braid wire pattern set within alayered polymer composition. Another approach is to vary the cylindricaldiameter and wall thickness of the catheter. Alternatively, a variety ofdifferent spiral-cuts can be introduced into the wall of the catheter,thereby increasing flexibility; these spiral cuts can either becontinuous or discontinuous in nature. However, there are no currentcatheters which combine both different types of materials as well asdifferent cut patterns in easy-to-assemble modules. Assembling acatheter from multiple modules, each of which is made from a differentmaterial, can be difficult because the physical properties of thesematerials make functional combination problematic, i.e., a stainlesssteel tube cannot be fused directly to a nitinol tube. However,assembling a catheter from different modules, each of which haddifferent properties, would allow one to tailor the catheter to meet theparticular requirements of different types of vascular anatomy.

The present invention provides a way for assembling catheter moduleseach having different physical properties. The catheter properties canbe tailored directly to meet a particular anatomical need. Thus, it ispossible to specifically control flexibility, resistance to plasticdeformation, axial torque transmission, and column strength of thecatheter in an anatomically specific manner. The modular catheters ofthe present invention are particularly useful for supporting a guidewireand/or delivering an agent through a vessel stenosis or tortuous anatomyas is often encountered in the cardiovascular or neurovascular systems.

SUMMARY OF THE INVENTION

Embodiments of the present invention provide a catheter that comprisesat least one proximal tubular module and a distal tubular module, eachof the tubular modules having at least one section with spiral cuts,each pair of adjacent tubular modules are coupled by a joint, the jointcomprising, (a) at least one snap-fit connector on a first tubularmodule and a snap-fit acceptor positioned on the adjacent tubularmodule, the snap-fit connector being elastically deformable whenengaged, and (b) at least one stabilizing element, including, a tongueelement positioned on the first tubular module or the adjacent tubularmodule, and a groove element positioned on the opposite, first tubularmodule or the opposite, adjacent tubular module.

In some implementations, the spiral-cuts comprise a plurality ofinterrupted spiral cuts.

The snap-fit connector may form a cantilever joint. In furtherimplementations, the snap-fit connectors comprise a stem structure and alocking structure, wherein the width of the locking structure at thewidest point as measured between opposite sides of the locking structureis greater than the width of the stem structure, and the snap-fitacceptor comprise a stem void and a locking void and wherein the widthof the locking void at the widest point measured between opposite sidesof the locking void is greater than width of the stem void. In certainembodiments, the locking structure can be formed in an oval shape andthe snap-fit acceptor comprises a locking void formed in a circularshape. The snap-fit connector can bend at the cantilever joint at anangle ranging from about 0.1 to about 90° with respect to a lineparallel to a longitudinal axis running parallel with one of the atleast one proximal tubular modules or the distal tubular module.

In some embodiments, the snap-fit connector forms a barb structure whichwhen inserted into the snap-fit acceptor, then, after insertion deployslaterally and remains parallel during and after insertion with respectto a line parallel to the longitudinal axis of one of the at least oneproximal tubular modules or the distal tubular module. In someimplementations, the barb structure comprises an arrow shaped structureformed from two shafts.

In some embodiments, the distal tubular module is formed from Nitinol.Alternatively, the distal module can be formed from stainless steel ofSAE grade selected from 304, 316, 402, and 440, 17-7 precipitationhardened stainless steel (PH), or Nickel Cobalt Alloy (MP35N).

To protect the joint between adjacent tubular modules, at least aportion of the joint can be enclosed with a tubular cover.

The catheter can comprise at least two cut openings, a first and asecond cut opening that are positioned on the at least one proximaltubular modules or the distal tubular module. In some implementations,both cut openings are positioned on the distal tubular module. In otherimplementations, one cut opening is positioned on the distal tubularmodule and the second cut opening is positioned on one of the at leastone proximal tubular modules. In some implementations, a filament isthreaded in a spiral configuration around the outside of a tubularmodule. One end of the filament is positioned in the first cut openingand the other end of the filament is positioned in the second cutopening.

The filament can be fixed in position at the first and second openings.The filament can also be threaded in either clockwise orcounterclockwise configuration around the one or more tubular modules onwhich is included. The filament can be fixed on one or more of theproximal tubular modules or the distal tubular module by at least onering. In addition, the cross-sectional area of the filament can becircular, square, triangular, rectangular, half-circle or trapezoidal inshape.

In some embodiments, the catheter comprises between 2 and 20 tubularmodules.

In some implementations, a polymer forming a jacket may be used to coverat least a portion of one or more of the at least one proximal tubularmodules or the distal tubular module. In some implementations, thepolymer jacket may be formed from nylon, polyether block amide, PTFE(polytetrafluoroethylene), FEP (fluorinated ethylene propylene), PFA(perfluoroalkoxy alkane), PET (polyethylene terephthalate) or PEEK(polyether ether ketone).

In some embodiment of the catheter according to the present invention,the at least one proximal tubular module and the distal tubular moduleinclude an inner lumen and wherein at least a portion of the inner lumenof the proximal or distal tubular modules is coated with an innerlining. In some implementations, the inner lining may be formed fromnylon, polyether block amide, PTFE (polytetrafluoroethylene), FEP(fluorinated ethylene propylene), PFA (perfluoroalkoxy alkane), PET(polyethylene terephthalate) or PEEK (polyether ether ketone).

There are a number of ways in way the snap-fit connector and snap-fitacceptor can be secured to ensure a robust connection between adjacenttubular modules. For instance, the snap-fit connector and snap-fitacceptor can be glued together, welded together, and soldered to eachother.

The at least one proximal tubular module and the distal tubular modulecan be formed from the same material or alternatively, from differentmaterials. In certain embodiments, one or more of the at least oneproximal tubular module is formed from stainless steel and the distaltubular module is formed from Nitinol. In some embodiments, one or moreof the at least one tubular module and the distal tubular module isformed from a polymer. In some implementations, one or more of the atleast one proximal tubular module and the distal tubular module isformed from a braided composite of metal and polymer.

In some embodiments, the outer diameter of a proximal tubular moduleadjacent to the distal tubular is the same as the outer diameter of thedistal tubular module. In alternative embodiments, the outer diameter ofthe adjacent proximal tubular module is greater than the outer diameterof the distal tubular module.

In some implementations, the inner diameter of the distal tubular moduleis smaller than the inner diameter of the adjacent proximal tubularmodule. Alternatively, the inner diameter of the adjacent proximaltubular module can be equal to the inner diameter of the distal tubularmodule.

One or more of the at least one proximal tubular modules can have thesame flexibility as the distal tubular module. Alternatively, the distaltubular module can have a greater flexibility than the flexibility ofone or more of the at least one proximal tubular modules.

In some embodiments, the distal end of the distal tubular module has acrown. In some implementations, the crown comprises a plurality ofcurvilinear elements. In particular implementations, the crown comprises5-20 curvilinear elements. The curvilinear elements may be sinusoidal inshape.

In embodiments of the catheter of the present invention, the catheterfurther comprises a tip that is attached to the crown of the distaltubular module. In some embodiments, the tip is tapered and furthercomprises radiopaque material impregnated within the tip material. Thetip may be from a metal, such as, but not limited to, gold. The tip canbe implemented as a hollow tubular body that is conically tapered. Afilament may be spirally wound around a distal portion of the distaltubular module and the tip, and both the filament and tip can be coveredwith a jacket.

In some embodiments, the catheter is coated a hydrophilic lubricatingpolymer.

Embodiments of the catheter of the present invention also provide acatheter that comprises at least one proximal tubular module and adistal tubular module, each of the tubular modules having at least onesection with spiral cuts, each pair of adjacent tubular modules beingcoupled by a joint, the joint comprising an interlocking shape having aplurality of protruding sections and receiving sections that mate withthe protruding sections, each of the adjacent tubular modules in thepair having one or more of the plurality of protruding sections and theplurality of receiving sections.

In some implementations, the interlocking shape of the joint comprises apattern of zig-zags. Alternatively, the interlocking shape of the jointcomprises a wave form. The catheter joint may be covered with a jacket.

In some embodiments of the catheter of the present invention, the distaltubular module comprises at least one least one section having aspiral-cut, distal tubular module is formed from a shape-memory metal,wherein a segment or section of the distal tubular module is set in acurvilinear shape along a central luminal axis of the tubular modulesuch that a constant cross-sectional lumen is maintained around thecentral luminal axis when the curvilinear shape is assumed by the distaltubular module. In some embodiments, At least a portion of the distaltubular module may be formed from Nitinol. In other embodiments, thedistal tubular module is formed from a stainless steel material selectedfrom the group of consisting of a stainless steel of SAE grade selectedfrom 304, 316, 402, and 440, 17-7 precipitation hardened stainless steel(PH), Nickel Cobalt Alloy (MP35N) and mixtures thereof. Alternatively,the distal tubular module can be formed from a polymer. In someimplementations, the section of the distal tubular module set in acurvilinear shape along maintains an angle ranging from about 0° toabout 90° with respect with a segment of the distal tubular module notset in a curvilinear shape. In other embodiments the section of thedistal tubular module set in a curvilinear shape along maintains anangle ranging from about 0° to about 180° with respect with a segment ofthe distal tubular module not set in a curvilinear shape. Thecurvilinear section be straightened using a guidewire. In someembodiments, the guidewire employed is tapered. In some implementations,section of the distal tubular module preset in a curvilinear shapeconverts to an angle of about 45° with respect with a segment of thedistal tubular module not set in a curvilinear shape when the guidewireis withdrawn from the tubular module. In other implementations, thesection of the distal tubular module preset in a curvilinear shapeconverts to an angle of about 180° with respect with a segment of thedistal tubular module not set in a curvilinear shape when the guidewireis withdrawn from the tubular module.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1(a) shows a front view of one embodiment of modular catheter thepresent invention.

FIG. 1(b) shows a blown up view of a portion of the embodiment shown inFIG. 1(a).

FIG. 2(a) shows side view of the embodiment shown in FIG. 1(a).

FIG. 2(b) shows an embodiment of an interrupted spiral cut patternincorporated in one or both of the proximal and distal tubular modularaccording to the present invention.

FIG. 2(c) shows another embodiment of an interrupted spiral cut patternaccording to the present invention.

FIG. 2(d) shows another embodiment of an interrupted spiral cut patternaccording to the present invention.

FIG. 2(e) shows a plan view of a snap-fit joint used to couple tubularmodules according to the present invention.

FIG. 2(f) shows another embodiment of an interrupted spiral cut patternaccording to the present invention.

FIG. 2(g) shows another embodiment of an interrupted spiral cut patternaccording to the present invention.

FIG. 2(h) shows another embodiment of an interrupted spiral cut patternaccording to the present invention.

FIG. 2(i) shows another embodiment of an interrupted spiral cut patternaccording to the present invention.

FIG. 3 shows a flattened view of an embodiment of an interruptedspiral-cut pattern according to the present invention.

FIG. 4(a) shows an engaged flattened two dimensional view of oneembodiment of a snap fit joint having a snap-fit connector and snap-fitacceptor according to an embodiment of the present invention.

FIG. 4(b) shows the snap-fit joint of FIG. 4(a) separated.

FIG. 5(a) shows a flattened two dimensional view a second embodiment ofanother embodiment of a snap-fit joint including a snap-fit connectorand snap-fit acceptor according to the present invention.

FIG. 5(b) shows a view of the snap-fit connector of the snap-fit jointshown in FIG. 5(a).

FIG. 6(a) shows a perspective view of an embodiment of a proximaltubular module, distal tubular module and snap-fit joint according tothe present invention.

FIG. 6(b) shows another angled perspective view of the embodiment shownin Figure

FIG. 6(c) shows an enlarged plan view of a snap-fit connector at the endof a tubular module according to an embodiment of the present invention.

FIG. 6(d) shows a perspective view of the snap-fit joint shown in FIGS.6(a)-6(c) connecting two tubular modules.

FIG. 6(e) shows a perspective view of a stabilizing element used tosecure a snap-fit joint between tubular modules according to anembodiment of the present invention.

FIG. 6(f) shows a perspective view of the snap-fit joint of FIGS.6(a)-6(d) in an uncoupled condition.

FIG. 6(g) shows another front view of a snap-fit joint according to anembodiment of the present invention.

FIG. 6(h) shows a side view (approximately 90° turn) of the snap-fitjoint of FIG. 6(g) in which the stabilization element is clearlydepicted.

FIG. 6(i) shows another side view (approximately 270° turn) of thesnap-fit joint of FIGS. 6(g) and 6(h).

FIG. 6(j) shows a bottom view (approximately 180° turn) of the snap-fitjoint of FIGS. 6(g) through 6(i).

FIG. 6(k) shows a cross sectional view in a plane perpendicular to thelongitudinal axis of an embodiment of a tubular module according to thepresent invention of one embodiment of the present invention.

FIG. 6(l) shows a side, flattened view of a snap-fit joint betweentubular modules according to the present invention in which a snap-fitacceptor is cantilevered at an angle to the longitudinal axis of themodule according to an embodiment of the present invention in theprocess of assembly.

FIG. 6(m) shows a perspective, flattened view of the snap-fit joint ofFIG. 6(l) shows a bottom, flattened view of the snap-fit joint of FIG.6(l) in the process of assembly.

FIG. 6(n) shows a top, flattened view of the snap-fit joint of FIGS.6(l) and 6(m) in the process of assembly.

FIG. 6(o) shows a bottom, reversed view of the snap-fit shown of FIGS.6(l) to 6(n) in the process of assembly.

FIG. 6(p) shows an enlarged side view of a cantilevered snap-fit jointshown in FIGS. 6(1) to 6(o) according to an embodiment of the presentinvention in the process of assembly.

FIG. 6(q) shows an enlarged perspective view of the cantileveredsnap-fit joint of FIGS. 6(l) to 6(q) in the process of assembly.

FIG. 6(r) shows an exploded perspective view of the cantileveredsnap-fit joint of FIGS. 6(l) to 6(q) in the process of assembly.

FIG. 6(s) another exploded perspective view of the cantilevered snap-fitjoint, as viewed from an angle 90° counterclockwise with respect to theview shown in FIG. 6(r) in the process of assembly.

FIG. 6(t) shows a cross-sectional view of the snap-fit joint in a planeperpendicular to the longitudinal axis of the catheter which illustratesbeveling of the snap-fit connector and acceptor in a locked position.

FIG. 7(a) shows a photomicrograph of a side view of a snap-fit jointthat couples two tubular modules according to an embodiment of thepresent invention.

FIG. 7(b) shows a photomicrograph of the snap-fit joint of FIG. 7(a) asrotated approximately 60° about the longitudinal axis with respect tothe photograph shown in FIG. 7(a).

FIG. 7(c) shows a photomicrograph of the snap-fit joint of FIGS. 7(a)and 7(b) as rotated approximately 60° about the longitudinal axis withrespect to the photograph shown in FIG. 7(b).

FIG. 7(d) shows a photomicrograph of a top view of the snap-fit joint ofFIGS. 7(a) to 7(c).

FIG. 7(e) shows a photomicrograph of the snap-fit joint of FIGS. 7(a) to7(d) as rotated approximately 60° about the longitudinal axis withrespect to the photograph shown in FIG. 7(d).

FIG. 7(f) shows a photomicrograph of the snap-fit joint of FIGS. 7(a) to7(d) as rotated approximately 30° about the longitudinal axis withrespect to the photograph shown in FIG. 7(d).

FIG. 8(a) shows one view of another embodiment of a joint (slightlyseparated) for coupling two tubular modules according to the presentinvention which employs interlocking sinusoidal shapes.

FIG. 8 (b) shows another view of the joint shown in FIG. 8(a) as rotatedapproximately 30° about the longitudinal axis.

FIG. 8(c) shows a perspective view of the joint (separated) of FIGS.8(a) and 8(b).

FIG. 8(d) shows a perspective view of the joint shown in FIGS. 8(a) to8(c) in a coupled state.

FIG. 8(e) shows a side view of another embodiment of joint (slightlyseparated) for coupling two tubular modules according to the presentinvention which using interlocking triangular shapes.

FIG. 8(f) shows another view of the joint shown in FIG. 8(e) as rotatedapproximately 30° about the longitudinal axis.

FIG. 8(g) shows a perspective view of the joint (separated) of FIGS.8(e) and 8(f).

FIG. 8(h) shows a perspective view of the joint shown in FIGS. 8(e) to8(g) in a coupled state.

FIG. 9(a) shows a cross-sectional view showing wall thickness of twoconnecting tubular modules according to the present invention in theplane of the longitudinal axis according to an embodiment of the presentinvention.

FIG. 9(b) shows a cross-sectional view of another embodiment of wallthickness of two connecting tubular modules according to an embodimentof the present invention.

FIG. 9(c) shows a cross-sectional view of yet another embodiment of wallthickness of two connecting tubular modules according to an embodimentof the present invention.

FIG. 10(a) shows a side view of an embodiment in which the outerdiameter of one of the tubular modules (proximal) is larger than theouter diameter of a tubular module (distal) to which it is connected.

FIG. 10(b) shows a longitudinal cross-sectional view of the embodimentshown in FIG. 10(a)

FIG. 10(c) shows a side view of the embodiment of the tubular modulesshown in FIG. 9(c).

FIG. 10(d) shows a perspective longitudinal cross-sectional view of theembodiment of FIGS. 9(c) and 10(c).

FIGS. 10(e) and 10(f) show that the joint may also be covered with acrimped metal that firmly covers and bonds the connected tubularmodules. FIG. 10(e) shows a joint covered with crimped metal and FIG.10(f) shows a joint 137 covered with crimped metal 1036.

FIG. 11(a) shows a side view in which a filament is wrapped around atubular module according to an embodiment of the present invention.

FIG. 11(b) shows a photograph of a side view of a tubular module havinga wrapped filament according to an embodiment of the present invention.

FIG. 11(c) shows a photograph of a curved tubular module having awrapped filament according to an embodiment of the present invention.

FIG. 11(d) shows a cross-sectional view of the embodiment shown in FIG.11(a).

FIG. 11(e) shows a perspective cross-sectional view of the embodiment ofFIGS. 11(a) and 11(d).

FIG. 12(a) shows a side view of a tubular module including a cut openingaccording to an embodiment of the present invention.

FIG. 12(b) shows a perspective cross-sectional view of the embodimentshown in 12(a) in the perpendicular plan across the cut opening.

FIG. 12(c) shows a photograph of a tubular module having a cut openingaccording to an embodiment of the present invention.

FIG. 12(d) shows a photograph of the tubular module shown in FIG. 12(c)rotated to depict the edge of the cut opening.

FIG. 13 shows another view of a tubular module having a wrapped filamentterminating the cut opening.

FIG. 14 shows a side view of the end of a distal tubular module having asecond cut opening in an general L shaped and a crown.

FIG. 15(a) shows a perspective view of the distal tubular module of FIG.14 and tip having a filament inserted into the second cut opening.

FIG. 15(b) is an enlarged view of the section of FIG. 15(a) outlined indashed line.

FIG. 15(c) shows another perspective view of the distal tubular moduleof FIG. 14 having a filament inserted into the second cut opening.

FIG. 16(a) shows a cross-sectional view of a modular catheter having anelongated tip attached to a distal tubular module according to anembodiment of the present invention.

FIG. 16(b) is an enlarged view of the section of FIG. 16(a) outlined indashed line.

FIG. 16(c) is a side view of the embodiment shown in FIGS. 16(a) and16(b).

FIG. 16(d) shows perspective a view of another embodiment of a tip thatcan be used with the modular catheter according to the presentinvention.

FIG. 16(e) shows a perspective view of a crown face of a distal tubularmodule.

FIG. 16(f) shows a perspective view illustrating the reduced surfacearea of the attachment portion without additional surface features.

FIG. 17(a) shows a perspective end view of an embodiment in which afilament is wrapper around the tubular module and tip attached to thetubular module is threaded, with a guidewire exiting from the tip.

FIG. 17(b) shows a side view of the embodiment shown in FIG. 17(a).

FIG. 17(c) shows a cross-section of the shown in FIG. 17(b).

FIG. 18(a) shows a perspective view of an embodiment of a reentrycatheter vessel dissection tip according to the present invention.

FIG. 18(b) shows a perspective view of another embodiment of a reentrycatheter vessel dissection tip according to the present invention.

FIG. 18(c) shows a perspective view of another embodiment of a reentrycatheter vessel dissection tip according to the present invention.

FIG. 18(d) shows a perspective view of another embodiment of a reentrycatheter vessel dissection tip according to the present invention.

FIG. 19(a) shows a side view of an embodiment of a distal tubular modulehaving side port exits and coupled to a vessel dissection tip havingwings in a top-down orientation according to the present invention.

FIG. 19(b) shows a perspective view of the embodiment shown in FIG.19(a) as rotated by 90°.

FIG. 19(c) shows an enlarged view of the section of FIG. 19(b) outlinedin dashed line.

FIG. 19(d) shows a side view of a distal tubular module having side portexits according to an embodiment of the present invention.

FIG. 19(e) shows a top view of the distal tubular module shown in FIG.19(d).

FIG. 19(f) shows a bottom view of the distal tubular module shown inFIGS. 19(d) and 19(e),

FIG. 19(g) shows a perspective view of the distal tubular module ofFIGS. 19(d) to 19(f).

FIG. 20(a) shows a side view of a distal tubular module having aflexible hooking section with shape memory according an embodiment ofthe present invention.

FIG. 20(b) shows an end view of the distal tubular module of FIG. 20(a).

FIG. 21(a) shows a side view of a distal module having a flexible,curvilinear section using material shape memory according to anotherembodiment of the present invention.

FIG. 21(b) shows an end view of the distal tubular module of FIG. 21(a).

FIG. 22 shows a side view of a portion of a distal tubular module havinga flexible curvilinear section using material shape memory according toan embodiment of the present invention.

FIG. 23 is a cross-sectional view illustrating a distal tubular modulehaving a curvilinear section that is straightened by a guidewireextending through the tubular module and tip.

FIG. 24 is a cross-sectional view illustrating withdrawal of theguidewire, allowing the curvilinear section to begin to assume itscurvilinear shape.

FIG. 25 is a cross-sectional view following on FIG. 24, illustrating thecurvilinear section adapted for side-branch access.

FIG. 26 is cross-sectional view showing a portion of the distal tubularmodule according to an embodiment of the present invention within anartery, with a shape-memory curvilinear section accessing a side branch.

FIG. 27 is cross-sectional view of the artery showing a portion of thedistal tubular module according to an embodiment of the presentinvention within an artery, with a shape-memory curvilinear sectionaccessing a side branch.

FIG. 28(a) shows a cross-section of an example section of an arterysystem having a main artery and a side-branch artery, a modular catheterwith a shape memory curvilinear section and guidewire according to thepresent invention is positioned in the main artery.

FIG. 28(b) shows the view of FIG. 28(a) in which the guidewire has beenwithdrawn, allowing the curvilinear section to assume a bent shape.

FIG. 28(c) shows the view of FIG. 28(b) with the guide wire and tipaligning for access into the side branch.

FIG. 28(d) shows as side view of the tip of the catheter inserted intothe side branch and the guidewire extended out of the tip of thecatheter through the side branch.

FIG. 28(e) shows the view of FIG. 28(d) with the catheter advancedthrough the side branch over the guidewire.

FIG. 29(a) shows a cross-section of an example section of an arterysystem having a main artery and a side-branch artery, a modular catheterwith a shape memory curvilinear section in a bent shape and guidewireaccording to the present invention is positioned in the main artery.

FIG. 29(b) shows the view of FIG. 29(a) after the catheter has beenwithdrawn backwards and torqued to angle the tip toward the opening ofthe side branch.

FIG. 29(c) shows the view of FIG. 29(b) with the tip of the catheterfurther advanced into the side branch.

FIG. 29(d) shows the view of FIG. 29(c) after a guidewire has beeninserted and the catheter has advanced through the side branch over theguidewire.

FIG. 30(a) shows a cross-section of an example section of an arterysystem having a main artery, a side-branch artery off of the mainartery, and a second side branch off of the first side branch. A pathwayfor a catheter through the system is shown.

FIG. 30(b) shows a cross-section view of FIG. 30(a) shows the view of30(a) in which a modular catheter according to the present invention hasadvanced through the first side branch past the opening of the secondside branch.

FIG. 30(c) shows a cross-section view of FIG. 30(b) after the guidewirehas been withdrawn allowing the curvilinear section of the distaltubular module to bend.

FIG. 30(d) shows a cross-section view of the entry of the tip andportion of the curvilinear section of the modular catheter in the secondbranch.

FIG. 30(e) shows the catheter advanced over a guidewire through thesecond branch.

DETAILED DESCRIPTION

Referring to FIGS. 1(a) and 1(b), a catheter 100 is formed from at leasttwo tubular modules 110, 120, generally referred to as a proximal 110and distal 120 tubular modules. Each tubular module has at least onesection which can have at least one spiral-cut section. The spiral-cutsection may extend along the full length of the tubular module or may bepositioned only along one or more portions of the tubular module. Thespiral-cut may be continuous or form an interrupted spiral pattern. Incertain embodiments, there may be more than two tubular modules, e.g.,2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 . . .or up to n, tubular modules linked together. If there are multipletubular modules, e.g., >2 tubular modules, the additional tubularmodules serve or act as extensions of the proximal, tubular module. Thetubular modules may be formed from hypotubes, which in certainembodiments may contain patterned cuts positioned on one end of thetubular module. The tubular modules may be formed from the same ordifferent materials and may have the same or different outer or innerdiameters. For example, the tubular modules can be made from similarmetals (metals having similar physical properties, e.g., ultimatetensile strength (UTS), % elongation, or modulus of elasticity), twodifferent metals, polymers, or formed from a combination of polymers andmetals.

In one embodiment, the tubular modules may be joined together by aplurality of snap-fit connectors and snap-fit acceptors which arepositioned on one end of either the same or different adjacent tubularmodules.

The structure of the snap-fit connectors may vary. For example, in oneembodiment, the snap-fit connector comprises a stem structure and alocking structure. The width of the locking structure at the widestpoint, as measured between opposite sides of the locking structure, isgreater than width of the stem structure at its widest point, asmeasured between opposite sides of the stem. The shape of lockingstructure can vary. In one embodiment, the locking structure is an oval,while in a second embodiment, the shape is circular or semicircular.Other shapes for the locking structure are encompassed by the invention,including, square, rectangular, trapezoidal, diamond or triangular.

The snap-fit acceptor comprises a stem void and a locking void and, ispositioned opposite the snap-fit connector on the opposing or adjacenttubular module. The structure of the snap-fit acceptor is the cut-outimage corresponding to the geometric structure of the snap-fitconnector.

FIGS. 1(a) and (b) show an overview of the structure of the catheter100. In the embodiment shown, there are two tubular modules, a proximaltubular module 110 and a distal tubular module 120. As used herein, theterms “proximal” and “distal” refer to the proximity of the tubularmodule to the hub 190 or the proximity to the cardiovascular system. Inother words, the proximal tubular module is positioned closer to the hub190 and more distant, as measured along the length of the catheter, fromthe heart, while the distal module is positioned closer to the heartand, thus, the coronary arteries. However, these terms only denoterelative position and are not limiting with respect to the structure,length, shape or number of the tubular modules.

The proximal and distal tubular modules can be made from similar metals,different metals, polymers, or a combination of polymers and metals.Examples of materials that may be used include stainless steel (SST),nickel titanium (Nitinol), or polymers. Examples of other metals whichmay be used include, super elastic nickel titanium, shape memory nickeltitanium, Ti—Ni, nickel titanium, approximately, 55-60 wt. % Ni,Ni—Ti—Hf, Ni—Ti—Pd, Ni—Mn—Ga, Stainless Steel (SST) of SAE grade in the300 to 400 series e.g., 304, 316, 402, 440, MP35N, and 17-7precipitation hardened (PH) stainless steel, other spring steel or otherhigh tensile strength material or other biocompatible metal material. Inone preferred embodiment, the material is superelastic or shape memory,nickel titanium, while in another preferred embodiment, the material isstainless steel.

The proximal and distal modules of present invention can include, inentirety, or in only in selected sections, a superelastic alloygenerally referred to as “a shape-memory alloy.” Elements made of suchshape memory alloys have the ability to resume their original shapeafter being deformed to such a degree that if they were made from anordinary metal, they would undergo permanent deformation. Superelasticalloys useful in the invention include: Elgiloy® and Phynox® springalloys (Elgiloy® alloy is available from Carpenter TechnologyCorporation of Reading Pa.; Phynox® alloy is available from Metal Imphyof Imphy, France), SAE grade 316 stainless steel and MP35N (NickelCobalt) alloys which are available from Carpenter Technology corporationand Latrobe Steel Company of Latrobe, Pa., and superelastic Nitinolwhich is available from Shape Memory Applications of Santa Clara, Calif.Further information regarding one or more of these alloys is disclosedin U.S. Pat. No. 5,891,191.

The term “superelastic” refers to alloys having superelastic propertiesthat include at least two phases: a martensitic phase, which has arelatively low tensile strength and which is stable at relatively lowtemperatures; and an austenitic phase, which has a relatively hightensile strength and which is stable at temperatures higher than themartensitic phase. Superelastic characteristics generally allow themetal to be deformed by collapsing and deforming the metal and creatingstress which causes the Nitinol to change to the martensitic phase. Moreprecisely, when stress is applied to a specimen of a metal such asNitinol exhibiting superelastic characteristics at a temperature at orabove that which the transformation of the martensitic phase to theaustenitic phase is complete, the specimen deforms elastically until itreaches a particular stress level where the alloy then undergoes astress-induced phase transformation from the austenitic phase to themartensitic phase. As the phase transformation progresses, the alloyundergoes significant increases in strain with little or nocorresponding increases in stress. The strain increases while the stressremains essentially constant until the transformation of the austeniticphase to the martensitic phase is complete. Thereafter, further increasein stress is necessary to cause further deformation. The martensiticmetal first yields elastically upon the application of additional stressand then plastically with permanent residual deformation. If the load onthe specimen is removed before any permanent deformation has occurred,the martensitic specimen elastically recovers and transforms back to theaustenitic phase. The reduction in stress first causes a decrease instrain. As stress reduction reaches the level at which the martensiticphase transforms back into the austenitic phase, the stress level in thespecimen remains essentially constant (but less than the constant stresslevel at which the austenitic crystalline structure transforms to themartensitic crystalline structure until the transformation back to theaustenitic phase is complete); i.e., there is significant recovery instrain with only negligible corresponding stress reduction. After thetransformation back to austenite is complete, further stress reductionresults in elastic strain reduction. This ability to incur significantstrain at relatively constant stress upon the application of a load andto recover from the deformation upon the removal of the load is commonlyreferred to as superelasticity.

As discussed above, suitable superelastic alloys include nickel titanium(Nitinol) consisting essentially of 49 to 53 atom percent of Ni, Cu—Znalloy consisting essentially of 38.5 to 41.5 wt % of Zn, Cu—Zn—X alloycontaining 1 to 10 wt % of X (X═Be, Si, Sn, Al, or Ga), and Ni—Al alloyconsisting essentially of 36 to 38 atom percent of Al. Nitinol isespecially preferable. The mechanical properties of Nitinol can bechanged as desired by replacing part of Ti—Ni alloy with 0.01 to 30.0atom percent of another element X (X═Cu, Pd, or Zr) or selecting thereduction ratio of cold working and/or the conditions of the final heattreatment. The buckling strength yielding stress when a load isincreased) of the super elastic alloy used is 5 to 200 kg/mm² (22° C.),preferably 8 to 150 kg/mm², and the recovery stress (yielding stresswhen a load is decreased) is 3 to 180 kg/mm² (22° C.), preferably 5 to130 kg/mm². Alternatively, the tubular modules may be formed frompolymers. Examples of polymers include polyimide, PEEK, nylon,polyurethane, polyethylene terephthalate (PET), latex, HDHMWPE (highdensity, high molecular weight polyethylene) and thermoplasticelastomers.

The tubular modules may be made, for example, by forming a pipe of asuper elastic metal and then removing the parts of the pipe where thenotches or holes are to be formed. The notches, holes or cuts can beformed in the pipe by laser (YAG laser, for example), electricaldischarge, chemical etching, mechanical cutting, or a combined use ofany of these techniques. See U.S. Pat. No. 5,879,381 to Moriuchi et al.,which is incorporated by reference herein, in its entirety.

After deformation by heating and deformation into a preset shape, e.g.,a curvilinear shape, the tubular module can be cooled. The tubularmodule is then restrained in the deformed condition within a deliverysystem to facilitate the insertion into an artery. Once the physicalrestraint on the tubular module is removed, the superelastic tubularmodule can return to its original undeformed shape, i.e., curvilinear.

In one embodiment, the proximal tubular module 110 may be made of 316SST and the distal tubular module 120 is made of 17-7 SST. In anotherembodiment, the proximal tubular module 110 is made of 17-7 SST, whilethe distal tubular module 120 is made of Nitinol. Either the proximaltubular module 110 or the distal tubular module 120 may be made from abraided composition of materials as well. In other embodiments, eitherthe proximal tubular module 110 or the distal tubular module 120 may bemade from a cable or a braided wire.

Each tubular module 110, 120 may have several different types ofspiral-cut patterns, including both continuous as well as discontinuousspiral-cut patterns. The different spiral-cut patterns may bedistributed on the same or different tubular modules.

The spiral-cut sections provide for a graduated transition in bendingflexibility, as measured by pushability, kink resistance, axial torquetransmission for rotational response, and/or torque to failure. Forexample, the spiral-cut pattern may have a pitch that changes toincrease flexibility in one or more areas of the tubular module. Thepitch of the spiral-cuts can be measured by the distance between pointsat the same radial position in two adjacent threads. In one embodiment,the pitch may increase as the spiral-cut progresses from a proximalposition to the distal end of the catheter. In another embodiment, thepitch may decrease as the spiral-cut progresses from a proximal positionon the catheter to the distal end of the catheter. In this case, thedistal end of the catheter may be more flexible. By adjusting the pitchand the cut as well as the uncut path of the spiral-cuts, thepushability, kink resistance, torque, flexibility and compressionresistance of the catheter, i.e., the tubular modules, may be adjusted.Thus, tubular modules having different rigidity or flexibility can becombined. For example, a comparatively rigid tubular module could becombined with relatively flexible tubular module. This combination couldbe further combined with a comparatively rigid of comparatively flexibletubular module.

By combining tubular modules with varying rigidity (conversely,flexibility), the catheter can traverse within a wide variety ofdifferent vasculature, especially, when the vascular anatomy istorturous or the lumen of the vasculature is compromised or obstructed,partially or completely, such as a Chronic Total Occlusion (CTO). Themodular structure also provides for the ability to effectively transmittorque across the length of the catheter without kinking or narrowing orcollapse of the lumen of the tubular modules. This combination oftubular modules with varying rigidity or flexibility allows theflexibility of the catheter to be adjusted across its length. Inaddition, the varying rigidity enables the flexibility of modularsections to go from more rigid to more flexible and then back to rigidagain. This modulation of flexibility/rigidity across the length of thecatheter allows it to be advanced into and function in variousanatomical lumens and across lumen obstructions.

The modulation of flexibility/rigidity across the length of the cathetercan be accomplished in a number of ways. For example, by varying thespiral-cut pattern variables (pitch, interruptions) and transitioningbetween spiral-cut patterns the flexibility/rigidity of a tubular modulemay be controlled. In addition, the spiral-cut pattern allows thecross-sectional diameter of the lumen to be maintained when the tubularmodule is bent or curved. Spiral-cut sections having different cutpatterns may be distributed along the length of the tubular module. Thespiral-cut patterns may be continuous or discontinuous along the lengthof the module. For example, there may be 1, 2, 3, 4, 5, 6, 7, . . . nspiral-cut sections along the length of the module. The spiral-cutsections may be continuous or interrupted. Within each section aconstant cut pattern may be present, but across different sectionswithin a tubular module, the cut patterns may vary, e.g., in terms ofpitch. Each section may also contain a variable pitch pattern within theparticular section. Each spiral-cut section may have a constant pitch,e.g., in the range of from about 0.05 mm to about 10 mm, e.g., 0.1 mm,0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm,1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm, 3.5 mm, 4.0 mm, etc. The pitch may alsovary within each section. The pitches for different spiral-cut sectionsmay be same or different. Alternatively, the catheter may be formed fromtubular modules have a continuously changing spiral-cut pattern alongthe length of the catheter. The orientation or handedness of spiral-cutsections in the modules may also vary within the spiral-cut sections.

The width of the spiral cuts can vary, e.g., from about 1 micron toabout 100 microns.

For an interrupted spiral-cut section, the interrupted spiral patterncan be designed such that each turn or rotation of the spiral includes aspecific number of cuts, Nc (e.g., 1.5, 2.5, 3.5, 4.5, 5.5, etc.). Nccan also be whole numbers, such as 2, 3, 4, 5, . . . n, as well as otherreal numbers, such as 2.2, 2.4, 2.7, 3.1, 3.3, etc. At a given Nc, theuncut extent α and the cut extent β can be chosen as α=(360−(β*Nc))/Ncsuch that each rotation has Nc number of repeat patterns each comprisinga cut portion of extent β adjacent an uncut portion of extent a. Forexample, at Nc=1.5, 2.5, and 3.5, the following table shows examplechoices of various embodiments for α and β:

Nc = 1.5 Nc = 2.5 Nc = 3.5 β (°) α (°) β (°) α (°) β (°) α (°) 230 10140 4 90 12.13 229 11 139 5 89 13.13 228 12 138 6 88 14.13 227 13 137 787 15.13 226 14 136 8 86 16.13 225 15 135 9 85 17.13 224 16 134 10 8418.13 223 17 133 11 83 19.13 222 18 132 12 82 20.13 221 19 131 13 8121.13 220 20 140 14 80 22.13 219 21 129 15 79 23.13 218 22 128 16 7824.13 217 23 127 17 77 25.13 216 24 126 18 76 26.13 215 25 125 19 7527.13 214 26 124 20 74 28.13 213 27 123 21 73 29.13 212 28 122 22 7230.13 211 29 121 23 71 31.13 210 30 120 24 70 32.13 209 31 119 25 6933.13 208 32 118 26 68 34.13 207 33 117 27 67 35.13 206 34 116 28 6636.13 205 35 115 29 65 37.13

FIG. 1(a) shows one embodiment of the catheter in which two tubularmodules, a proximal tubular module 110 and distal tubular module 120,are joined together. In the embodiment, shown, a tip, 170, is attachedto a crown 160 at a distal end of the distal tubular module 120. The twotubular modules are connected together at a joint 130. The joint 130 isformed by snap-fit connector 140 and snap-fit acceptor 150 asillustrated in FIG. 1(b), where the snap-fit connector 140 is locked-inor snapped into the snap-fit acceptor 150; tubular modules are hollowand have an inner lumen as well as an outer wall. A hub 190 can bepositioned at one end of the catheter 100, and an intermediate tubularsection 180 connects the hub 190 and proximal tubular module 110. Anytype of hub can be used with the catheter.

FIGS. 2(b)-(i) show embodiments of spiral-cut sections of a tubularmodule that may be used on different portions of the proximal and distaltubular modules shown in FIG. 2(a). The distal tubular module, 120comprises an interrupted spiral-cut sections 210 (shown enlarged in FIG.2(b)), 220 (shown enlarged in FIGS. 2(c)), and 230 (shown enlarged inFIG. 2(d)) The proximal tubular module 110 comprises interruptedspiral-cut sections 240 (shown enlarged in FIG. 2(f)), 250 (shownenlarged in FIG. 2(g)), 260 (shown enlarged in FIGS. 2(h)) and 270(shown enlarged in FIG. 2(i)). The joint 130 between the proximal anddistal tubular modules is shown in FIG. 2(e). Note, in the embodimentshown, the snap-fit connector and span-fit acceptor are flush with theouter surface of the tubular modules, i.e., the outer portions of thesnap-fit connector and acceptor do not protrude beyond the outerdiameter of the tubular modules.

In the embodiments shown in FIGS. 2(a)-2(i), the interrupted spiral-cutsare represented as being discontinuous. A detailed view of oneembodiment of these spiral-cuts is shown in FIG. 3, which depicts aportion of an unrolled (or flattened) tubular module having aninterrupted spiral-cut pattern. The spiral-cut tube section of thetubular module shows a single, spiral ribbon portion having adjacentturns 310, 320 which are substantially defined and separated by aninterrupted spiral cut path width 330. The spiral cut path width 330includes alternating open or cut portions 340 and uncut portions 350.The spiral pathway width 330 is composed of alternating cut and uncutsections 340 and 350 is angled with respect to a circumference of thetubular portion (in other words, the pitch angle θ shown in FIG. 3 ofless than 90°).

As illustrated in FIG. 3, each helically-oriented uncut portion 350 hasan arcuate extent “α” and each helically-oriented cut portion has anarcuate extent “β.” Angles α and β can be expressed in degrees (whereeach complete helical turn is 360°). The uncut portions can bedistributed such that adjacent uncut portions 350 are not in axialalignment (or “staggered”) with each other along a direction parallel tothe longitudinal axis L. As shown in FIG. 3, the uncut portions 350 onevery other turn of the interrupted spiral cut width 330 can be axiallyaligned.

The spiral-cut patterns of each tubular module can be formed fromcontinuous spiral-cut sections, interrupted spiral-cut sections, or ahybrid of both types of spiral-cut patterns, where the various patternsare arranged in any order. The interrupted cut spiral modules have theability to maintain a concentric lumen area while in a bentconfiguration, even in sharp bends of small radii. The ability tomaintain a concentric lumen enables smooth wire movement, in eitherdirection within the tubular lumen, without resulting in a deformationof the lumen. Additionally, using superelastic materials such as Nitinolfor the spiral cut segments, allows segment to bend in tight curvesthrough various vascular passageways without permanent lumendeformation.

The length of each of the tubular modules can vary. For example, thelength of the proximal tubular module 110 can range from about 100 cm toabout 140 cm, about 120 cm to about 140 cm, about 125 cm to about 135 cmor about 50 cm to 100 cm. The length of the distal tubular module 120can range from about 15 cm to about 35 cm, about 10 cm to about 25 cm,about 20 cm to about 45 cm, about 30 cm to about 50 cm, about 5 cm toabout 15 cm or about 1-5 cm.

In certain embodiments, the distal tubular module may be formed into amicrocatheter. The microcatheter is capable of navigating over aguidewire into remote vasculature. The microcatheter may be capable ofcrossing a lesion and delivering the guidewire and/or contrast mediaacross the lesion followed by, e.g., deployment of an interventionaltreatment element across the lesion, immediately restoring blood flow.The interventional treatment element may be a stent, a coil, a flowdiverter, a flow restoration element, a thrombectomy element, aretrieval element, an aspirator or a snare

FIGS. 4(a)-(b) and 5(a)-(b) illustrate two different, preferredembodiments of snap-fit connectors and snap-fit acceptors that can beused to couple tubular modules according to the present invention. Theembodiments are shown in a two-dimensional representation where thetubular module is flattened in a plane. In FIG. 4(a), the proximaltubular module 110 which in this embodiment is formed from SST, isconnected at the joint 130 to the adjacent distal tubular module, whichis formed, in this embodiment, from Nitinol, by a snap-fit connector 140and snap-fit acceptor 150. In addition to the snap-fit connector 140 andsnap-fit acceptor 150, two stabilizing elements, 450, 451 may bepositioned on either lateral side of the snap-fit connector/snap-fitacceptor 140, 150. In the embodiment shown, the stabilizing elements arerectangular in shape, however, the shape of the stabilizing elements arenot limited to a rectangular shape (e.g., trapezoidal, square ortriangular).

There may be a plurality of snap-fit connectors and snap-fit acceptorsconnecting two adjacent tubular modules ranging from 1, 2, 3, 4, 5, 6,7, 8, 9, 10 . . . n. The snap-fit connector and/or the snap-fit acceptorcan be positioned on either the proximal and/or the distal tubularmodules. For example, the snap-fit connector can be on the distaltubular module and the snap-fit acceptor can be on the proximal tubularmodule or, alternatively, the snap-fit connector can be on the proximaltubular module and the snap-fit acceptor can be on the distal tubularmodule. The snap-fit connector and snap-fit acceptor form a pair onadjacent tubular modules.

The stabilizing elements can prevent the tubular modules from rotatingindependently, maintain concentric alignment and allow for transmissionof torque across the proximal and distal modules along the length of thecatheter. The management of torsion and shear stress in the modularcatheter is thereby improved. The ratio between the shear stress andstrain of a material is an elastic constant of the module (G). When anapplied torque is balanced by the internal stress of the material, thetorque on the cros-section resulting from sheer stress is:

Torque(T)=GΘ/L*J

where Θ is the angle of rotation, L is the length of the section and Jis known as the “polar second moment of area”.

With respect to hollow shafts, such as catheters, the expression for Jis:

J=π(D ⁴ −d ⁴)/32

where D and d are the outside and inside diameters of the catheter(i.e., tubular modules). These equations yield an indication of theamount of torque that can be safely transferred along a catheter toprevent undue torsion.

The stabilizing elements can be implemented as tongue elements 450, 451that fit into corresponding grooves 460, 461 on the opposite tubularmodule. Also in this embodiment, the snap-fit connector 140 forms acantilevered joint formed on the distal tubular module 120. In theembodiment shown, the snap-fit connector 140 includes a circular lockingsection 410 connected to the body of the proximal tubular module by astem section 420. The proximal tubular module 110 includes acorresponding snap-fit acceptor 150, a space or receptacle, including acircular portion 430 to receive circular section 410 and a rectangular440 portion to receive the stem section 420. FIG. 4(b) shows the twotubular modules 110, 120, and joint 130 in FIG. 4(a) in an explodedview. The tubular modules are joined together by inserting the snap-fitconnector 140 into the snap-fit acceptor 150.

FIGS. 5(a) and (b) illustrate another embodiment of a snap-fit joint. Inthis embodiment, the snap-fit connector, 510, has two arms, 530, 540,each having a respective triangular or trapezoidal shaped head (alsoreferred to as arrow or barb shaped), 550, 560, positioned at one end.The arms 530, 540 have a springiness property and have leeway to pivotlaterally with respect to the longitudinal axis, 570, of the tubularmodule. In FIG. 5(b), the snap-fit connector 510 is shown in the openposition in which arms 530, 540, are displaced laterally relative to thelongitudinal axis 570 of the tubular module. When inserted into thesnap-fit acceptor, 520, the arms 530, 540 pivot inwardly and the anglebetween the arms and longitudinal axis of the tubular module decreases.After insertion, triangular shaped heads 550, 560 move or flex outwardlyagain as shown in FIG. 5(a) fixing the snap-fit connector 510 in thesnap-fit acceptor 520. In other embodiments, other designs for snap-fitjoints can be used including torsion and annular snap joints.

FIGS. 6(a)-6(j) illustrate various perspective views of the embodimentshown in FIGS. 4(a) and (b), where the proximal tubular module 110 andthe distal tubular module 120 are linked together using the snap-fitconnector 140 and snap-fit acceptor 150, together with stabilizingtongue and groove elements 450, 460. In the embodiment shown in FIGS.6(a)-6(j), the stabilizing elements 450 and the snap-fit connector 140are positioned at one end of a single tubular module 120. In otherembodiments, the snap-fit connector 140 and the stabilizing elements450, are positioned and employed on multiple tubular modules.Alternatively, each tubular module can contain a variety of differentsnap-fit connectors. For example, the snap connector, 140, shown in FIG.4(a), could be combined with snap connector 510, shown in FIG. 5(b).Additionally, the embodiment shown in FIG. 6(g) shows a tubular cover445 for the entire joint 130 or only a portion thereof, which can bemade of a polymer or other material, e.g., metal.

As noted above, the snap-fit connector 140, which can be positioned oneither the distal or proximal tubular modules 110, 120 may be formedfrom a stem structure 420 (FIG. 6(c)) which can be attached at acantilever joint 610 to one end of either the proximal or distal tubularmodule. The attachment forms a cantilever joint 610, which iselastically deformable, around which the stem structure 420 and lockingstructure 410 can bend at an angle θ ranging from of about 0° to about90° with respect to a line parallel to the longitudinal axis 620 of thefirst or second tubular module, as further illustrated in FIG. 6(l).FIGS. 6(l)-(o) show flattened views (where the tubular module has beencut, unrolled and laid flat) of the snap-fit connector 410 of cantileverjoint 610 in a raised position. FIG. 6(l) is a side or sagittal view ofthe raised cantilever joint. FIG. 6(m) shows the joint from theperspective of the external surface of the tubular module. FIG. 6(n)shows the join from a top external view, while FIG. 6(o) shows the jointfrom the perspective of the internal surface of the tubular module.FIGS. 6(p)-(s) show perspective views of the cantilever joint 610 withthe snap-fit connector 140 in a raised position.

In addition to the snap-fit connectors, 140, at least one stabilizingelement comprises a tongue element e.g., 450 in one of the tubularmodules and a groove element e.g., 460 in the connecting module. Thestabilizing element 450 may be positioned laterally to the snapconnector around the circumference of an end of the proximal or distaltubular module, 110, 120 (a second stabilizing including tongue element451 and groove element 461 are also shown in some of the figures (e.g.,FIG. 6(s)). The stabilizing elements may assume a variety of differentshapes, including, but not limited to, rectangular, trapezoidal, square,circular or triangular. Functionally, the role of the stabilizingelements 450 is illustrated in FIGS. 6(d)-(j). When the snap-fitconnectors and acceptor 140, 150 are joined together, the stabilizingelements shapes function to prevent the proximal and distal tubularmodules 110, 120 from rotating circumferentially at the joint 130 wherethe tubular modules have been connected. There may be one stabilizingelements (FIG. 6(e)), or alternatively there may be two or morestabilizing elements (FIG. 6(j)), e.g., 3, 4, 5, 6, 7, 8, 9, 10 . . . upto n stabilizing elements. The stabilizing elements allow for thetransmission of force (torque) along the longitudinal length of thecatheter.

The shape of the snap-fit connectors which are used to secure the twotubular modules together may vary. For example, in one embodiment, thesnap-fit connector 150 of the proximal tubular module 110 has anacceptor in the form of an oval 430 with a stem structure 440, while thesnap-fit connector 140 has complementary shape in the form of an oval410 and stem structure 420 which fits directly into the snap-fitacceptor 150. This joining is illustrated in FIGS. 6(d)-6(j) where thetubular modules 110, 120 are connected together, and in 6(a)-6(b) wherethe two tubular modules are shown in an exploded view or separated fromeach other. FIGS. 6(d)-(j) illustrate the snap-fit joint from severaldifferent views. In FIGS. 6(d)-(j), stabilizing elements 450 and thesnap connector 140 are positioned laterally with respect to each otheraround the distal tubular member.

Other shapes for the snap-fit connectors are encompassed herein,including semicircular, oblong, triangular, trapezoidal or irregular,either individually or in combination with other shapes. In thesedesigns, the maximum width of the locking structure 410, measuredbetween opposite sides, is greater than the width of the stem structure420. This configuration secures the snap-fit connector 140 within thesnap-fit acceptor, preventing them from pulling apart from each otherwithout first releasing the snap-fit connector.

The edges of the snap-fit connector 140 of the distal tubular module 120and the edges of the snap-fit acceptor 150 of the proximal tubularmodule 110 may be beveled to ensure that the snap-fit connector andsnap-fit acceptor are securely connected and will not separate ordislodge after insertion into the patient as illustrated in FIG. 6(t).The angle θ of the bevel may range from about 0° to about 90° withrespect to a line formed along the longitudinal axis of the proximal anddistal tubular modules. The angle θ can range from about 5° to about90°, about 20° to about 70°, or 40° to about 60°. The snap-fit connectorand snap-fit acceptor can also be joined by gluing, soldering, laserwelding, welding or enclosing within a ring or securing a jacket(tubular) over the joint. These modifications prevent the snap-fit fromlifting out-of-plane.

As illustrated in FIGS. 7(a)-(f), which depict photomicrographs of thejoint between snap-fit connectors and snap-fit acceptors according toembodiments of the present invention, the joint between the snap-fitconnector 140 and snap-fit acceptor 150 may be flush, i.e., the surfaceof the snap-fit connector does not protrude above the outer surface(outer diameter) of the snap-fit acceptor and is level with the outersurface of the tubular modules.

FIGS. 8(a)-(h) illustrate other embodiments of the types of jointsbetween the proximal tubular module 110 and the distal tubular module120. In these embodiments, the proximal and distal tubular modules 110,120 have interlocking shapes including protruding sections 810, 830 andreceiving sections 820, 840 at the joint 135 which interlock with eachother. In the embodiment shown in FIGS. 8(a)-(d), the protruding section810, 830 and receiving sections 820, 840 take the form of a wave,sinusoid, meandering or curvilinear elements. In another embodiment,FIGS. 8(e)-(h), interlocking shape 137 comprises protruding sections815, 835 and receiving sections 825, 845 in the form of a triangular orzig-zag pattern. The interlocking shapes of the protruding and receivingsections used can all be the same, or there may be more than one type ofprotruding and receiving section on either the proximal and/or distaltubular modules.

In general, embodiments can include one or more, 1, 2, 3, 4, 5, 6, 7, 8,9, 10 . . . n, protruding sections and receiving sections. For example,in the embodiments illustrated in FIGS. 8(a)-(h), there are threeprotruding sections and corresponding receiving sections. Functionally,the protruding sections e.g., 810, 830 and receiving sections e.g., 820,840, prevent the proximal and distal tubular modules, 110, 120 fromrotating circumferentially at the joints where the tubular modules havebeen connected. The interlocking shape joints can be covered with atubular jacket to help secure the joint.

As illustrated in cross-sectional views in FIGS. 9(a)-(c), the proximaland distal tubular modules 110, 120 may have the same or different inneror outer diameters. The outer diameter of the proximal tubular module110 or the distal tubular module 120 can range from about 0.5 mm toabout 1 mm. The inner diameter of the proximal tubular module 110 or thedistal tubular module 120 can range from about 0.10 mm to about 3.5 mm.

As shown in FIG. 9(a), the inner diameter 910 of proximal tubular module110 and the inner diameter 920 of distal tubular module 120 may be thesame or approximately the same. In addition, the outer diameter 930 ofthe proximal tubular module 110 and the outer diameter 940 of the distaltubular module 120 may be the same or approximately the same.

Alternatively, as shown in FIG. 9(b), the proximal tubular module 110and the distal tubular module 120 may have the same inner diameter 911,921, but have different respective outer diameters 931, 941 (FIG. 9(b)).In this particular embodiment, the proximal tubular module 110 has alarger outer diameter 931 than the outer diameter 941 of the distaltubular module 120. This is further illustrated in the embodiments shownin FIGS. 10(a) and 10(b). In this embodiment, at the joint between theproximal tubular member 110 and the distal tubular member 120, theproximal tubular member 110 and the distal tubular member 120 form a 90°angle with respect to each other due to the differences in their outerdiameters 931, 941. FIG. 10(a) illustrates the difference in outerdiameter 931 of the proximal tubular module 110 as compared to outerdiameter 941 of the distal tubular module 120. FIG. 10(b) shows across-sectional view of FIG. 10(a). In the embodiment shown here, theinner diameter of both the proximal tubule 911 and distal tubular module921 are the same.

In yet another embodiment, the proximal tubular module 110 can have botha larger inner diameter 912 and outer diameter 932 than the inner andouter diameters 922, 942, respectively, of the distal tubular module 120(FIG. 9(c)). This distinction is further illustrated in FIGS. 10(c) and10(d), which show partial and extended cross-sectional views of theembodiment shown in FIG. 9(c). In this embodiment, at the joint 130between the proximal tubular member 110 and the distal tubular member120, the inner diameter 922 and the outer diameter 942 of the distaltubular module 120 at the joint 130 are initially the same as the innerdiameter 912 and outer diameter 932 of the proximal tubular module 110.At the joint, the inner diameter 922 and outer diameter 942 of thedistal tubular module 120 decreases in size until the inner diameter 922and the outer diameter 942 of the distal tubular module 120 are smallerthan the inner diameter 912 and outer diameter 932 of the proximaltubular module 110. The decreases in size of the inner diameter 922 andouter diameter 942 may be linear or non-linear.

The proximal tubular module 110 or the distal tubular module 120 canhave a varying diameter across its length, e.g., a taperedconfiguration. The tapering can be in any direction or may only bepresent along a portion of the tubular module.

The wall thickness of the proximal tubular module 110 and the distaltubular module 120 may vary, for example to increase flexibility towardthe distal tip. In the embodiment shown in FIG. 9(a), the wall thickness950 of the proximal tubular module 110 may be the same as the wallthickness 960 of the distal tubular module 120. In the embodiment shownin FIGS. 9(b) and 10(b), the wall thickness 951 of the proximal tubularmodule 110 is greater than the wall thickness 961 of the distal tubularmodule 120. However, in this embodiment the inner diameters 911, 921 ofthe proximal and distal tubular modules 110, 120 remain the same whilethe outer diameters 931, 941 of the proximal and distal tubular modules110, 120, are different. In FIGS. 9(c), 10(c) and 10(d) the wallthickness of the proximal tubular module 952 tapers at the joint withthe distal tubular module. Similarly, the wall thickness 962 of thedistal module tapers at the joint with the proximal tubular module. Thethickness of the wall can taper. For example, the wall thicknesses 952,962 are larger away from the joint 130 and can be the same or differentwith respect to each other. Any changes in inner diameter or outerdiameter from one tubular module will incorporate a transition from onetubular module to the next which can be tapered.

Depending on the material as well as the structural requirements interms of flexibility, the wall thickness of a tubular module at anypoint can vary, e.g., from about 0.05 mm to 2 mm, e.g., 0.05 mm to about1 mm, about 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8mm, 0.9 mm, 1.0 mm, etc. The inner diameter of a tubular module canvary, e.g., from about 0.1 mm to about 2 mm, or from about 0.25 mm toabout 1 mm, e.g., about 0.2 mm, about 0.3 mm, about 0.4 mm, about 0.5mm, about 0.6 mm, about 0.7 mm, about 0.8 mm, about 0.9 mm, about 1 mm,about 2 mm, about 2.5 mm, about 3 mm thickness. The outer diameter atubular module can also vary, e.g., from about 0.2 mm to about 3 mm,e.g., including about 0.2 mm, about 0.3 mm, about 0.4 mm, about 0.5 mm,about 0.6 mm, about 0.7 mm, about 0.8 mm, about 0.9 mm, about 1 mm,about 1.1 mm, about 1.2 mm, about 1.3 mm, about 1.4 mm, about 1.5 mm,about 1.6 mm, about 1.7 mm, about 1.8 mm, about 1.9 mm, about 2.0 mm,about 2.5 mm, about 3 mm thickness. The wall thickness of the tubularmodule wall, the inner diameter and the outer diameter can each beconstant throughout the length of the tubular module, or vary along thelength of the tubular module.

The joint between tubular modules may be coated or covered with a jacketor a sleeve such as a polymer. FIGS. 10(a)-10(d) depict an embodiment inwhich the coating comprises two separate sections, a coating 1010 thatcovers the distal end of the proximal tubular module 110 as well as thejoint 130, and a second coating 1020 that covers or coats a distalportion of the distal tubular module 120; the coatings 1010, 1020, maybe the same or different. In other embodiments a single coating (i.e.,either a jacket or spray coating) can be used. This jacket or sleevefurther bonds the elements of the joint together, preventing theproximal tubular module 110 and distal tubular module 120 fromdisconnecting from each other. The entire catheter 100 or only a portionof the catheter 100, e.g. the proximal or distal tubular modules, can becoated. The coating or jacket can provide a conduit for fluid along thelength of the catheter. The coating may also be limited to cover onlythe joint 130 where two tubular modules are connected together.Alternatively, the joint can be covered with a ring to secure the joint130. As depicted schematically in FIGS. 10(e) and 10(f) the joint mayalso be covered with a crimped metal that firmly covers and bonds theconnected tubular modules. FIG. 10(e) shows a joint 135 covered withcrimped metal 1035 and FIG. 10(f) shows a joint 137 covered with crimpedmetal 1036

In addition, the inner walls, i.e., lumen, of the proximal and distaltubular modules can be coated with an inner lining that both protectsthe tubular modules and facilitates transport of additional toolsdevices such as guidewires and balloons through the tubes of thecatheter to distal locations. The inner lining can extend along aportion of the proximal or distal tubular modules or can extendthroughout the entire length of the tubular modules.

The jacket as well as the inner lining can be made from a polymer, e.g.,by enclosing the tube wall with a co-extruded polymeric tubularstructure of single of multiple layers and heat shrinking the tubularstructure, or coating the tube wall via a dip coating process. Thepolymer jacket material can be nylon, polyether block amide, PTFE(polytetrafluoroethylene), FEP (fluorinated ethylene propylene), PFA(perfluoroalkoxy alkane), PET (polyethylene terephthalate) or PEEK(polyether ether ketone). Further, the distal tube portion 120 (or theentire length of catheter 100) may be coated with a hydrophilic polymercoating to enhance lubricity and trackability. Hydrophilic polymercoatings can include, but are not limited to, polyelectrolyte and/or anon-ionic hydrophilic polymer, where the polyelectrolyte polymer caninclude poly(acrylamide-co-acrylic acid) salts, apoly(methacrylamide-co-acrylic acid) salts, apoly(acrylamide-co-methacrylic acid) salts, etc., and the non-ionichydrophilic polymer may be poly(lactams), for examplepolyvinylpyrollidone (PVP), polyurethanes, homo- and copolymers ofacrylic and methacrylic acid, polyvinyl alcohol, polyvinylethers, snapicanhydride based copolymers, polyesters, hydroxypropylcellulose, heparin,dextran, polypeptides, etc. See e.g., U.S. Pat. Nos. 6,458,867 and8,871,869. The coating can be applied by a dip coating process or byspraying the coating onto the tube outer and inner surfaces.

In the process of spray coating, a coating formulation is applied to thesurface of the device using a nozzle apparatus. This apparatus has achamber for containing the coating formulation and an opening in fluidconnection with the chamber through which the coating formulation can bedispensed and deposited on the surface. To apply the coating formulationto the surface of the tubular modules of the catheter, the formulationis placed into the chamber of the nozzle apparatus and charged using ahigh voltage using a conductor. Once the coating formulation in thechamber is charged, it carries the same charge as the conductor. As aresult, the formulation and conductor repel each other. This repulsiveforce discharges the coating formulation through the opening of thenozzle to create streams of droplets. An additional gas source can beused for atomizing the coating formulation.

One or both of the tubular modules 110, 120 can further include afilament 1100. FIGS. 11(a) through 11(e), depict a filament 1100 wrappedaround the distal tubular module 120. In FIGS. 11(a)-11(c), the filament1100 is wrapped around the distal tubular module 120 in a spiral manner.FIGS. 11(a) and 11(b) show the catheter, i.e., the tubular modules, in astraight configuration while FIG. 11(c) shows the catheter, the tubularmodules, in a curved configuration. In general, the filament 1100 isdisposed on the outer surface of the distal tubular module 120 andencircles all or part of the distal tubular module 120. The filament1100 proceeds in a spiral fashion around the distal tubular module 120and forms a spiral structure on the outer surface of the tubular module.In certain embodiments, the spiral filament can be wrapped around theproximal tubular module. The filament may be wrapped in a clockwise orcounter-clockwise manner around the tubular modules.

The filament 1100 can be adhered to or attached to the tubular modulesin variety of different ways. In one embodiment, the filament 1100 issecurely coupled to the tubular module fitting one or more bands orcover around it and the tubular module. Other implementations caninclude wedging, hooking, affixing, bonding or gluing the filament intoor onto the tubular module. FIG. 11(a) shows bands 1102, 1104 thatsecurely fasten the filament 1100 to the distal tubular module 120.Additionally, in some embodiments, the jacket that covers one or more ofthe tubular modules also covers the filament 1100 as well. This coverfirmly secures the filament in place with respect to the tubular module.

A lubricious coating or film may be added over the jacket to facilitatemovement of the catheter through blood vessels. The lubricious coatingcan be composed of, for example, silicone or hydrogel polymers or thelike, such as polymer networks of a vinyl polymer, polyalkylene glycols,alkoxypolyethylene glycols or an uncrosslinked hydrogel, e.g.,Polyethylene oxide (PEO).

In other embodiments such as in FIGS. 11(d) and 11(e), the filament 1100is threaded over the coating 1020 on one or more of the tubular modules.FIGS. 11(d) and 11(e) show a cross section view of the filament attachedto the outer surface of the distal tubular module 120. The cross-sectionview of the filament 1100 may be circular, as illustrated in FIGS. 11(d)and (e). Alternatively, the cross-section of the filament 1100 may havedifferent shapes, for example, square, rectangular, triangular, hexagon,semicircular, or oblong. The filament 1100 may be used for screwing (orunscrewing) through small tapering diameter vessels or occlusivesegments within the arterial wall, for example, such as de novo plaquearea and restenotic segment of the target vessel. As the filament 1100comes into contact with the vessel and/or occlusive segments, and torqueis applied to the catheter, the filament facilitates forward motion ofthe catheter through intermediate vessels and plaque in order to reachthe target vessel. For example, when the catheter system 100 is rotated,the filament 1100 can be used to facilitate drilling or boring through acalcified atheromatous plaque. The filament 1100 converts rotationalmotion into linear motion and torque into a linear force, thereby makingit easier for the catheter to proceed through the blood vessels,especially in regions of comparative calcification. The filament 1100can also be used as a securing mechanism, such as to secure the catheterto a specified location within the blood vessels, by creating a clampingforce against the walls of the blood vessels. To remove the catheter,the catheter would have to be backed-out using the same screw-likemotion but in the opposite direction in order to prevent stripping thewalls of the blood vessel. Because of its rounded surface, a circularcross-section minimizes damage to the arterial walls. The pitch angle ofthe spiral thread may remain constant. Having the spiral thread segmentadherent to the outside of the module allows the pitch angle to remainconstant over the length of the spiral segment.

The filament can be the same material or a different material from thetubular modules 110, 120. Alternatively, in some embodiments, thefilament 1100 can be made of a polymer.

The proximal tubular module 110 and the distal tubular module 120 caninclude at least one additional cut opening through the wall, asillustrated in FIGS. 12(a)-12(d) and FIG. 14. The cut openings may be onthe same or different tubular modules.

A first cut opening 1200, illustrated in FIGS. 12(a)-(d), can bepositioned within the interrupted spiral. The first cut opening 1200 maybe oriented orthogonally to the longitudinal axis 1400 of the tubularmodule or may be positioned at an angle relative to the longitudinalaxis 1400. As illustrated in FIG. 13, the filament 1100 can be attachedto the tubular module at the first cut opening 1200.

As illustrated in FIG. 14, a second cut opening 1300 may be shapedgenerally in the form of an “L” which is positioned at the distal end ofthe tubular module 120 near or adjacent to the crown 160 at which a tipsection 170 is secured to the tubular module 120. In one embodiment, thefirst cut opening 1200 and the second cut opening 1300 are located onthe same tubular module. As illustrated in FIGS. 15(a)-(c), the filament1100 can be attached at the second cut opening 1300.

The walls of the cut openings, 1200, 1300, may be beveled or chamfered.The angle θ of the bevel may range from about 20° to about 70°, or about40° to about 60° with respect to the long axis 1400 of the tubularmodule. The shape of the cut openings, 1200, 1300, may vary and may beoval, square, L-shaped (See, 1300, FIG. 14), V-shaped, curvilinear orcircular.

FIGS. 14, 15(a)-15(c) and 16(a)-16(f) illustrate one embodiment wherethe distal end of the distal tubular module 120 has a crown 160. Thecrown 160 may be made from a plurality of closed, curvilinear elementswhich can be sinusoidal or generally wave-form (meandering) in shape. Inone embodiment, there may be a plurality of curvilinear elements, e.g.,ranging from 5-20. FIGS. 15(a)-(c) show an embodiment where the tip 170is attached to the distal tubular module 120. The filament 1100 isattached to the cut opening 1300 of the distal end 160 of the distaltubular module 120. The distal tubular module 120 and tip 170 may becovered with a jacket 175. The jacket can act to secure the tip 170 tothe distal end 160 of the distal tubular module 120.

In one embodiment, shown in FIG. 16(a)-(d), the distal end 160 of thedistal tubular module 120 can attach to a tip 170. The tip may comprisea hollow tubular body and may be conically tapered as shown in FIGS.16(a) and 16(b). In addition, the hollow tubular body of the tip can bethreaded. The tip 170 may be coated with a jacket 175. FIG. 16(c) showsan illustration of a comparatively elongated tip 171, while FIG. 16(d)shows an illustration of a comparatively shorter tip 172. The tip may beconfigured with differences in tapering, durometer, rigidity, shape,length, radiopacity, profile, and composition as compared with eitherthe catheter or the proximal or distal tubular modules. The tip can bemade of a super-elastic alloy with shape memory. The shape of the tipcan be set by heat treatment. For example, the tip may be made from orincorporate radiopaque materials such as gold.

As illustrated in FIGS. 16(e) and (f), due to the curvilinear structure(e.g., prongs) of the crown 160, the surface area of the crown (SA1) canbe greater than the surface area of the distal end of the distal tubularmodule (SA2). The greater surface area of the crown allows for greatersurface area contact, and, therefore, binding, between the crown 160 andthe tip 170.

As depicted in FIGS. 17(a)-(c), a filament 1100 can be wound spirallyaround both the proximal or distal tubular modules 110, 120, and alsocan continue to spiral around the tip 170. In embodiments in which thetip is a hollow tube including threads, the filament can be fitted intothe threads of the tip as shown in FIG. 17(b). The filament 1100 mayproceed around all or only a portion of the tip 170. The filament may bewound around the modules in a clockwise or counter-clockwise spiralmanner. In other embodiments, the tip may be fabricated with a threadedstructure of its own. The filament of the tip may also be covered with ajacket.

In another embodiment, shown in FIGS. 19(a) and 19(b), a re-entry tipcan be coupled to the distal end of the distal tubular module with orwithout directly engaging the prongs of the crown 160. Furtherdescription of catheter re-entry is found in commonly owned and assignedU.S. patent application Ser. No. 14/854,242, entitled “Vascular Re-entryCatheter, which is incorporated by reference herein in its entirety.When used with a re-entry tip, the modular catheter can be used inprocedures involving re-entry into the true lumen after the creation ofa dissection plane.

Examples of re-entry tips are shown in FIGS. 18(a)-18(d). FIG. 18(a) isa re-entry tip 1810 having a smooth surface and two wings disposed oneither side of the re-entry tip. FIG. 18(b) is a re-entry tip 1820having divots in its surface around the entire diameter of the tip. FIG.18(c) is a re-entry tip 1830 having divots in its surface around theentire diameter of the tip and two wings disposed on either side of there-entry tip. FIG. 18(d) 1840 is a re-entry tip having a smooth surfaceand no wings.

As shown in FIGS. 19(b)-19(c), the modular catheter system 100 canfurther comprise at least one side port 1900. Some embodiments, as shownin FIGS. 19(a) and 19(d), have two side ports1900 a, 1900 b. More thantwo side ports can be used. In the embodiments having more than one sideport, the side ports can all be aligned linearly down the length of thecatheter system 100. In other embodiments, the side ports can be alignedaround the diameter of the catheter system 100. The side ports can beevenly spaced down the length of the catheter system 100, or they can bespaced at specific locations. In another embodiment, the side ports aredisposed only on the distal tubular module 120.

Referring to FIG. 19(a), side ports 1900 a and 1900 b can be positionedradially offset, between about 180° apart from each other, e.g., about180° (±10°). A re-entry tip 1810 includes wings 1811, 1812 also spacedapart by approximately 180°. In general, the radial displacement of theside ports relative to the wings may range from about 0° to 90°, e.g.,10°, 20°, 30°, 50°, 70° and 80°. In one embodiment, the positions of theside ports may be radially offset from the wings at about 90°. In thisway, when the two wings 1811 and 1812 are positioned in a stableconfiguration in the subintimal space of an artery, port 1900 a can befacing either toward or opposing the true lumen of the artery, and theport 1900 b can face the opposite side.

The side ports may be symmetrical in shape and can be circular,semicircular, ovoid, semi-ovoid, rectangular or semi-rectangular. Theside ports may have the same shape and size (i.e., surface area) or canbe different from each other and are configured to allow for passage ofa re-entry wire or another medical device through the ports. Thedimensions of the port may be adjusted to accommodate different types ofmedical devices or wires, e.g., with diameters ranging from about 0.05mm to about 1.0 mm. Erglis et al. Eurointervention 2010:6, 1-8. Thedistal tube portion 120 can contain more than two exit ports, e.g., 3,4, 5, 6, 7, 8 . . . n ports along its length direction and radiallydistributed as desired.

The side port may be beveled. The beveled configuration of the side portcan facilitate a re-entry wire with a bent tip to smoothly exit andregress from the side port. The angle θ of the bevel may range fromabout 0° to about 90°, including, 10° to about 90°, about 20° to about70°, or 40° to about 60°.

In one embodiment, at least two radiopaque markers and positioned alongdistal tubular portion 120 for aiding radiographic visualization of thepositioning of the catheter 100 in the vascular lumen. The markers caninclude a radiopaque material, such as metallic platinum,platinum-iridium, Ta, gold, etc., in the form of wire coil or band,vapor deposition deposits, as well as radiopaque powders or fillers,e.g., barium sulfate, bismuth trioxide, bismuth sub carbonate, etc.,embedded or encapsulated in a polymer matrix. Alternatively, the markerscan be made from radiopaque polymers, such as radiopaque polyurethane.The markers can be in the form of bands to encircle the outer sheath ofthe distal tubular portion.

The radiopaque markers configured as bands can be used to facilitatedetermination of the positions of the side ports while the distal tubeportion 120 is maneuvered in a subject's anatomy. The markers can alsobe configured as a partial band or patch which forms specific alignmentwith a corresponding side port. For example, one marker can be axiallyaligned with side port 1900 a, whereas a second marker can be axiallyaligned with side port 1900 b. Thus, like the radially oppositeconfiguration of the side ports 1900 a and 1900 b, the markers are alsoradially opposite to each other. In this manner, visualization of themarkers can be used to determine the orientation of the respective sideports. The markers can be configured in different shapes, e.g., partialcircumferential bands, or any other desired shapes, to facilitatedetermination of orientation of the ports.

The markers can also be configured as surface patches that enclose thecircumferences of the respective side ports 1900 a and 1900 b. In suchan embodiment, the marker positions that can be visualized directlycorrespond to the side port positions.

The markers should have sufficient size and suitableconfiguration/construction (e.g., the type of radiopaque material, loadamount of radiopaque material, etc.) such that they can be visualizedwith the proper radiographic aid.

The variable flexibility of the sections of the tubular modules alsofacilitates surgical procedures in which side-branch access is requiredor where tortuous vasculature is encountered such as in the centralnervous system. Given the ability to use a wide variety of combinationsfrom the base tube's material mechanical properties, the tubingdimensions (OD/ID), wall thickness, cut tubing's mechanical propertiesresulting from the cut pattern along the tube's (material composition,UTS, % Elongation modulus of Elasticity, and other combinations ofmaterial and mechanical properties (UTS, formulas defining cut pitchangle, cut width, helical cut arc length and uncut helical space betweennext helical arc cut), all enable the designer to tailor a variety ofmechanical properties defined throughout the running length of the cuttube. Such resulting properties such as stiffness, flexibility and usingthe shape memory properties define a preset curvilinear shape areprogrammable and changeable.

Additionally, such an induced shape memory form would require a greaterforce to straighten or diminish and maintain via a resistive load forcealong the cut and shape treated portion of the distal tubular segment,to orient the shape set portion of the tube to revert back into astraight linear concentric coaxial configuration, which would enable thecatheter to be advanced to the vascular target.

Such variables assembled together, to create a wide variety ofstructural shape combinations of tubular modules. These structuralshapes can easily be temporarily diminished inline by advancing thetubular modules over a wire track, e.g., a guidewire, which exhibitsmechanical properties of deformation that exceed the curvilinear shape'sspring constant. This temporary deformation enables advancement of thecatheter, the tubular modules, over the guidewire through the vascularanatomy. Simply put, the spring constant of the shaped curve portion isless than that of the wire segment it is tracking over. Once theretaining guidewire segment's spring constant is less than that of theset curvilinear shape, the cut shaped tube segment will revert back toits preset shape, unless acted upon by an additional other externalforces or vascular confinement.

The distal modules of the present invention can include portions thatbend or hook or are set in-place in a curvilinear shape through theapplication of shape memory. As noted above, super-elastic alloysincluding Nitinol have this property, which can be modified by heating.FIGS. 20(a) and 20(b) depict a side view and an end view, respectivelyof a distal end of a catheter according to the present invention thatincludes this feature. As shown in the side view, a portion of a distaltubular module 2020 includes at its distal end a curvilinear section2030 that bends. The bend can be at least one of: a curve, a sinusoidalcurve, a non-linear section, an angulation, a peak, a valley, asquiggle, curvilinear, and helical. The bend can have a variablestiffness. The bend can have a stiffness coefficient greater than theremaining portion of the elongated member.

The curvilinear section can bend from about 0° to about 180° withrespect to the longitudinal axis (L, FIG. 21(a)) of the tubular module.The curvilinear shapes of the section can vary and include, flush,simple curves, complex curves, reverse curves or double curves. Thelength of the curvilinear section can vary and may encompass only aportion or the entire length of the tubular module. In the embodimentshown in FIG. 20(a), the curvilinear section 2030 assumes the 45° unlessa force, e.g., a guidewire, is applied to straighten or otherwise alterits configuration. Force may be applied through a variety of means, suchas a guidewire which is inserted into the lumen of the tubular moduleand is co-axial with the lumen of the tubular module. The end view inFIG. 20(b) shows a lumen 2050 of the distal tubular module. Thiscross-section of the lumen remains constant during bending of thecurvilinear section 2030. This constant cross-sectional lumenfacilitates passage of wires and other devices through the vasculature.

The catheter can include a guidewire which can be passed through thelumen of the tubular modules. The tubular modules can be passed over theguidewire into an artery. Guidewires are typically comparatively thin,having a diameter in the order of about 0.254 mm to 0.457 mm. Guidewiresare capable of transmitting rotation from the proximal end of theguidewire to the distal end of the guidewire. This transmission allowsthe physician to controllably steer the guidewire through the branchesof the patient's arteries and manipulate the catheter to the intendedtarget site in the coronary artery. Additionally, the distal end of theguidewire should be sufficiently flexible to allow the distal portion ofthe guidewire to pass through sharply curved, tortuous coronary anatomy.

Among the common guidewire configurations used in angioplasty is thetype of guidewire illustrated in U.S. Pat. No. 4,545,390. Such a wireincludes an elongate flexible shaft, typically formed from stainlesssteel, having a tapered distal portion and a helical coil mounted to andabout the tapered distal portion. The generally tapering distal portionof the shaft acts as a core for the coil and results in a guidewirehaving a distal portion of increasing flexibility that is adapted tofollow the contours of the vascular anatomy while still being capable oftransmitting rotation from the proximal end of the guidewire to thedistal end so that the physician can controllably steer the guidewirethrough the patient's blood vessels. The characteristics of theguidewire are affected significantly by the details of construction asthe distal tip of the guidewire. For example, in one type of tipconstruction, the tapering core wire extends fully through the helicalcoil to the distal tip of the coil and is attached directly to asmoothly rounded tip weld at the distal tip of the coil. Such aconstruction typically results in a relatively stiff tip suitedparticularly for use when attempting to push the guidewire through atight stenosis. In addition to a high degree of column strength, such atip also displays excellent torsional characteristics.

In another type of tip construction, the tapered core wire terminatesshort of the tip weld. It is common in such a construction to attach avery thin metallic ribbon at one (proximal) end to the core wire and atits other (distal) end to the tip weld. The ribbon serves as a safetyelement to maintain the connection between the core wire and the distaltip weld in the event of coil breakage. It also serves to retain a bendformed in the ribbon to maintain the tip in a bent configuration as isdesirable when manipulating and steering the guidewire. Additionally, byterminating the core wire short of the tip weld, the segment of thehelical coil between the distal end of the core wire and the tip weld isvery flexible and floppy. The floppy tip is desirable in situationswhere the vasculature is highly tortuous and in which the guidewire mustbe capable of conforming to and following the tortuous anatomy withminimal trauma to the blood vessel. In another type of tip construction,the distal-most segment of the core wire is hammered flat (flat-dropped)so as to serve the same function as the shaping ribbon but as anintegral unitary piece with the core wire. The tip of the flat droppedsegment is attached to the tip weld. Guidewires are well known in theart and the appropriate choice of a guidewire for use the catheter ofthe present invention can be made by a medical professional, such as aninterventional cardiologist or interventional radiologist.

FIGS. 21(a) and 21(b) depict a side view and end view of anotherembodiment of a distal end of a catheter according to the presentinvention. In this embodiment, a distal tubular module 2120 includes atits distal end a curvilinear section 2130 that naturally assumes a 90°bend from the point at which it is connects to the remainder of thedistal tubular module (i.e., the horizontal axis) up to a tip 2140. Thecurvilinear section assumes the 90° bend unless a force is applied tostraighten or otherwise alter its configuration. The end view in FIG.21(b) shows a lumen 2150 of the distal tubular module. This lumen canmaintain a constant cross-section in distal tubular module lumen ismaintained within the curvilinear section 2130.

FIG. 22 shows a side view of still another embodiment of a distal end ofa catheter according to the present invention. In this embodiment, thecurvilinear section 2230 of a distal tubule module 2220 bends stillfurther, to approximately 180°, such that the tip 2240 point toward thedistal tubular module and aligns approximately parallel with thelongitudinal axis, L, of the distal tubular module.

FIGS. 23-25 shows three parts of a sequence in which the tubularmodules, include a curvilinear section together with a guidewire. Anyconventional guidewire may be used with the present invention. Forexample, the central core of the guidewire may be formed from Stainlesssteel, Durasteel™ or nitinol/Lastinite®. The guidewire may be coveredwith a polymer sleeve or a coil-spring tip and coated with a lubriciouscoating.

FIG. 23 is a cross-sectional view illustrating a distal tubular modulehaving a curvilinear section 2330 that is straightened-out by passingthe distal tubular module 2320 over a guidewire 2310 extending throughthe tubular module 2320 and tip 2340. As shown, the guidewire 2310extends through the end portion of the distal tubular module 2320,passing through the shape-memory, curvilinear section 2330, past the tip2340 of the tubular module. In this position, the guidewire 2310 keepsthe curvilinear section 2330 aligned or straight with respect to thelongitudinal axis (L) of the distal tubular module 2320 and prevents thecurvilinear section from bending in accordance with its shape memory. Inother words, the spring constant of the curvilinear section 2330 is lessthan that of the spring constant of the guidewire 2310 segment that thedistal tubular module 2320 is tracking over. If the spring constant ofthe retaining guidewire 2330 segment is less than the spring constant ofthe curvilinear section 2330, the curvilinear section 2330 will revertback to its preset shape, unless acted upon by an additional otherexternal forces or vascular confinement.

In FIG. 24, the guidewire 2310 has been withdrawn in the leftwarddirection (as shown by the arrow) from the tip 2340 and a distance (L1)within the preset curvilinear section 2330 of the distal tubular module2320. As shown in FIG. 24, as the guidewire 2310 is withdrawn, thepreset curvilinear section 2330 begins to bend and assume its presetshape as discussed above.

In FIG. 25, the guidewire 2310 has been withdrawn still further from theposition shown in FIG. 24, i.e., L2>L1, within the curvilinear section2330. As a result, the curvilinear section 2330 continues to bend inaccordance with its shape memory such that the angle between thedirection in which the tip 2340 faces and the longitudinal axis, L, ofthe distal tubular module 2320 (′P) is greater than 90°. The range ofbending ranges from about 0° to about 180° with respect to thelongitudinal axis, L. In this embodiment, the distal end of the distaltubular module in this position is configured in the shape of a“Shepherd's Hook” and is better adapted, in this configuration, toaccess side-branches in the arterial system or for access into tortuousvasculature.

FIG. 26 shows an example of the catheter and distal tubular module witha curvilinear section with shape memory as it can be applied forside-branch artery access. In the Figure, a main arterial branch 2602and a side-branch artery 2604 which joins to and branches-off from themain artery 2602 are shown. The distal end of a catheter, including adistal tubular module 2620, together with a preset, curvilinear section2630 and tip 2640 are shown. In the Figure, the guidewire 2610 has beenwithdrawn from the curvilinear section 2630, allowing the curvilinearsection to bend to about 180° with respect to the longitudinal axis ofthe tubular module (see, L, FIGS. 23-25, supra.).

As the catheter, which includes the distal tubular module 2620 is movedlaterally in the artery the curvilinear section 2630 can enter the sidebranch 2604. Note, a torqueing force may be applied to the catheter byrotating the hub which can rotate the proximal and distal tubularmodules about the central axis.

FIG. 28(a) shows a cross-sectional view of an arterial system whichcomprises a main vessel 2802 together with a single side branch artery(also referred to as a side branch) 2804. In the example shown, thediameter of the main artery 2802 is greater than the diameter of thefirst side-branch 2804. A distal tubular module 2820 is shown positionedin the artery 2802 where the distal tubular module extends past the sidebranch artery 2804. The guidewire 2810 extends past the end of thedistal tubular module 2820 and the tip 2840. The guidewire 2810 includesa tapered section 2814. As discussed above, the guidewire 2810straightens-out the pre-set, curvilinear section 2830 of the distaltubular module 2820.

FIG. 28(b) shows the guidewire 2810 partially withdrawn from the distaltubular module 2820, allowing the curvilinear section 2830 to bend. Thetip 2840 and the tapered end 2814 of the guidewire 2810 reposition inaccordance with the bending of the curvilinear section 2830 and enterinto the side branch of the artery 2804 or position the tip 2840allowing for entry into the side branch 2804.

In FIG. 28(c), the guidewire 2810 is withdrawn further from the distaltubular module 2820. The tip 2840 and the tapered end of the guidewire2814 are aligned with the axis of the side branch 2804.

In FIG. 28(d), the tapered end of the guidewire 2814 is extended pastthe tip 2840 into the side branch 2804. Then, in FIG. 28(e), the distaltubular module 2820 is advanced over the guidewire 2810 down through theside branch 2804.

FIG. 29(a) shows another method for enabling access to arterial sidebranches. As depicted, a distal tubular module 2920, including a preset,curvilinear section 2930 and tip 2940 are positioned in a main artery2902 with a guidewire having been withdrawn. The preset, curvilinearsection 2930 and tip 2940 are positioned past (in the forward movementdirection) the junction of the main artery 2902 with a side branch 2904.Because of shape memory in the preset curvilinear section 2930, thissection and the tip are in shown in a bent or Shepherd's Hook position.In the example shown, the tip is bent 180° in the reverse movementdirection, parallel to the longitudinal axis. The preset bend can alsobe at other angles (e.g., 45°, 90°, 120°, etc.). From this position, asthe distal tubular module 2920 is withdrawn, a torque force 2945 can beapplied to rotate the distal tubular module 2920 clockwise orcounterclockwise. The distal tubular module 2920 can then be insertedinto the side branch 2904.

FIG. 29(c) shows the distal tubular module 2920 and tip 2940 havingentered further into the side branch 2904 from the position shown inFIG. 29(b). In FIG. 29(c) the tip approaches alignment with the axis ofthe side branch 2904.

FIG. 29(d) shows the continued advancement of the distal tubular module2920 through a first side branch 2904. A guidewire 2910 can be used tostraighten the curvilinear section 2930 to enable the catheter toproceed through the lumen of the side branch 2804. Because of theengineered flexibility of the distal tubular module, the distal tubularmodules can bend to accommodate sharp turning angles 2924.

In short, in both single side branch access methods, the preset,curvilinear section of the distal tubular module is used in the mannerof a hook to create a secure anchor for advancement into side branches,ultimately allowing advancement of the catheter through multiplearterial vessel and side branches.

FIG. 30(a) shows an arterial system including a main artery 3002, a sidebranch artery 3004, and a secondary side branch 3006 coming off of theside branch 3004. A path 3008 for advancing a catheter through the mainartery 3002 and the two side branches 3004, 3006 is shown. FIG. 30(b)shows a distal tubular module 3020 extended through a side branch 3004in a manner discussed above with respect to FIGS. 28(a) to 28(e) andFIGS. 29(a) to 29(d). The tip 3040 and the tapered end of the guidewire3014 extend at an approximately right angle to the axis of the secondbranch 3006. In FIG. 30(c), the guidewire 3010 has been partiallywithdrawn and a torqueing force, 3045, 3046, has been applied to thedistal tubular module 3020. Because of the construction of the catheter,the torque is transmitted to the tip 3040 and curvilinear portions 3030(as shown by the curved arrows 3046). The torqueing force angles the tip3040 away from the axis of the first branch 3004. A combination oftorqueing force and lateral movement enable the tip 3040 to accesssecond side branch 3006 as shown in FIG. 30(d). In FIG. 30(e), theguidewire 3010 is advanced through the distal tubular module 3020 andtip 3040, allowing the distal tubular module 3020 to be transported overthe path defined by the guidewire 3010.

Because of the modular construction of the catheter system according tothe present invention, a family of microcatheters can be created byvarying the distal tubular module of the catheter system for use indifferent procedures. A microcatheter is typically a single-lumen devicethat can be loaded on a guidewire in order to track it to the targetlesion. The typical outer diameter (OD) ranges from about 1.30 mm on theproximal portion of the shaft to about 0.70 mm on the distal portion ortip of the shaft. The internal diameter of the lumen of the distaltubular module can vary and when used as a microcatheter can taper. Thetrackability and pushability of the distal tubular module can be variedas described above. The distal tubular module can be designed to addressspecific anatomical challenges, such as for use in antegrade proceduresor retrograde procedures, for use in peripheral vascular accessprocedures, or for use as a re-entry catheter. The distal tubular moduleand the proximal tubular module can be preassembled with the proximaltubular module being attached to one of a variety of distal tubularmodules. Or the distal tubular module and the proximal tubular modulecan be separate and assembled immediately prior to use.

The design of the distal tubular module can be varied such as by usingdifferent materials for fabrication. The in-line stacked variable wallthickness can also be varied, such as by simple inline stepped reductionin outer diameter while maintaining a constant inner diameter, bymachining or grinding the tubular module material to vary the wallthickness along the length of the tubular module, or by laser cutting,ablating, machining, or grinding the tubular module material to createspecific design features along the tubular module surface, such as ascrew thread design carved out of the tubular module material at aspecific location or along a defined length. The design of the distaltubular module 120 can also be varied through the use of stackedinterrupted spiral-cut patterns along the length of the tubular module.These interrupted spiral-cut patterns formula variables could includethe cut pitch angle, laser cut path width, or stacked variable cutpatterns along the length of the tubular module, for example having aformula for interrupted spiral-cut pattern of cut and non-cut degreesalong the helical cut.

Another specific example of a use for the modular catheter system wouldbe for creating a microcatheter device. Such micro catheter couldcomprise a base micro catheter as one of the tubular modules. This basemicrocatheter could be used for an antegrade approach, having tightlesion access and backup wire support. The second tubular module can beone of a variety of microcatheters. These devices could have peripheralvascular and neuro vascular arterial access and can be used in manydisease management applications and should not be limited to only theexample provided herewith.

EXAMPLES Testing Methodology:

The proximal tubular module and the distal tubular module can havedifferent flexibility, kinkability, torque to failure, torqueability,trackability, pushability, crossability, and rotational response. Avariety of different tests are available for testing flexibility,kinkability, torque to failure, torqueability, trackability,pushability, crossability, and rotational response. Various standardtests for these properties are known in the art.

The proximal tubular module and the distal tubular module can have thesame flexibility or different flexibilities. Flexibility is the qualityof bending without breaking. The flexibility of the tubular module isdependent on the material used, the interrupted spiral pattern, the wallthickness, the inner diameter and the outer diameter, and othervariables. Flexibility can be determined by one of the following testingmethods. One method of testing flexibility uses a proximal load cell tomeasure the ability of the device to advance and withdraw, with no lossof function or damage to the tortuous anatomy, over a specific bendangle. Alternatively, a roller system can be used to determine thesmallest radius of curvature that the device can withstand withoutkinking. Additionally, tests can be performed by a cantilever beam tomeasure force and bending angle by calculating F═[M×(% SR)]/(S×100) withangularity at 50° where F=flexibility, M=total bending moment, %SR=scale reading average, and S=span length. Another method of testingflexibility is to use one- and four-point bending tests to evaluateflexibility under displacement control using a ZWICK 005 testing machinewhich detects the force F and the bending deflection f when one end of adevice is grilled and the other end pressed with a plate moving at aconstant speed. The highest measured data describes the flexibility asdetermined by the equation E×I=(F×L³)/(3×f) (Nmm²) where I=moment ofinertia, E=Young modulus, L=bending length, f=bending deflection, andF=point force and E×I=flexibility.

The proximal tubular member and the distal tubular member can have thesame or different torque to failure or torque to break. Torque tofailure is the amount of twisting or rotational force the tubular membercan withstand before a plastic deformation of the catheter components, afracture or break occurs. One method for testing torque to failure isthrough the use of proximal and distal torque sensors which measure theamount of torque and the number of revolutions until device failure byrotating the device at a more proximal location and fixing the distalend while the device is routed through tortuous anatomy. Another testingmethod for calculating torque to failure is by testing torque strengthimmediately following submersion in 37±2° C. water for a set period oftime. With a guidewire in place, the device can be inserted into acompatible guiding catheter which is constrained in a two dimensionalshape to replicate access into the coronary anatomy until the distalmost 10 cm of the catheter is exposed beyond the guiding tip and isattached to a torque gauge to prevent rotation. The remainder of thecatheter body is rotated in 360° increments until distortion, failure,breaks, fractures, kinks, or other damage occurs along the catheter orat the catheter tip, or for a set number of rotations.

The proximal tubular member and the distal tubular member can have thesame or different torqueability. Torqueability is the amount of torque,or rotation, lost from one end of the tubular module to the other end ofthe tubular module when a rotational force is exerted on one end. Onemethod for testing torqueability is by using a proximal and distaltorque sensor to measure the amount of torque transmitted through thedevice by rotating the device at a more proximal location and fixing thedistal end while the device is routed through tortuous anatomy. Anothermethod for testing torqueability is by using an artery simulating devicefor PTCA training, such as the PTCA trainer, T/N: T001821-2, designed byShinsuke Nanto, M. D., which simulates a clinical tortuous path. Anindicator attached to the catheter tip and inserted through the hole ofa dial. The catheter body is connected to a rotator, for example T/N:T001923, and rotated clockwise in 90° increments to 1080°. The anglemeasured by dial attached to the indicator on the catheter tip is usedto calculate the ratio of the angle of rotation of the body to the angleof rotation of the tip, which corresponds with the amount of torque lostduring rotation.

The proximal tubular module and the distal tubular module can have thesame trackability or different trackabilities. One method for testingtrackability is to use a proximal load cell to measure the force toadvance the device through a tortous anatomy with or without the aid ofa guiding accessory.

The proximal tubular module and the distal tubular module can have thesame or different pushability. One method for testing pushability is touse a proximal and distal load cell to measure the amount of force thedistal tip of the device sees when a known force is being applied to onthe proximal end.

The proximal tubular module and the distal tubular module can have thesame or different crossability. One method for testing crossability isto use a proximal load cell to measure the ability of the catheterdevice to advance and withdraw over a specific lesion site without lossof function or damage to the tortuous anatomy. Additionally, a rollersystem can determine the worst lesion that the device can withstandwithout damage.

The proximal tubular module and the distal tubular module can have thesame or different rotational response. One method for testing rotationalresponse is by using proximal and distal rotation encoders to measurethe amount of rotation transmitted through the device by rotating thedevice at a more proximal location and keeping the distal end free whilethe device is routed through tortuous anatomy.

The scope of the present invention is not limited by what has beenspecifically shown and described hereinabove. Those skilled in the artwill recognize that there are suitable alternatives to the depictedexamples of configurations, constructions, and dimensions, andmaterials. The citation and discussion of any references in theapplication is provided merely to clarify the description of the presentinvention and is not an admission that any reference is prior art to theinvention described herein. All references cited and discussed in thisspecification are incorporated herein by reference in their entirety.While certain embodiments of the present invention have been shown anddescribed, it will be obvious to those skilled in the art that changesand modifications may be made without departing from the spirit andscope of the invention. The matter set forth in the foregoingdescription and accompanying drawings is offered by way of illustrationonly and not as a limitation.

1-65. (canceled)
 66. A catheter comprising: a first tubular module and asecond tubular module coupled to the first tubular module by a joint,the joint comprising: (a) at least one connector on the first tubularmodule and at least one acceptor positioned on the second tubularmodule, wherein the at least one connector and at least one acceptor arelevel with inner and outer surfaces of the first tubular module and thesecond tubular module when coupled together to define a continuous lumenwith a uniform diameter therethrough, and wherein the at least oneconnector prevents the first and second tubular modules from rotatingcircumferentially at the joint; and (b) at least one stabilizing elementpositioned on the first tubular module, wherein the at least onestabilizing element is level with inner and outer surfaces of the firsttubular module and the second tubular module when coupled together,wherein the at least one stabilizing element prevents the first andsecond tubular modules from pivoting with respect to each other, andwherein the stabilizing element has a different shape than the at leastone connector.
 67. The catheter of claim 66, wherein the at least oneconnector includes a cantilever joint.
 68. The catheter of claim 66,wherein the at least one stabilizing element does not include acantilever joint.
 69. The catheter of claim 66, wherein the secondtubular module is formed from Nitinol.
 70. The catheter of claim 69,wherein the first tubular module is formed from stainless steel of SAEgrade selected from 304, 316, 402, and 440, 17-7 precipitation hardenedstainless steel (PH), or Nickel Cobalt Alloy (MP35N).
 71. The catheterof claim 66, wherein at least a portion of the joint is enclosed with atubular cover.
 72. The catheter of claim 66, wherein a filament isthreaded in a spiral configuration around at least a portion of thefirst and second tubular modules.
 73. The catheter of claim 66, whereinat least a portion of at least one tubular module is covered with apolymer jacket.
 74. The catheter of claim 73, wherein the polymer jacketis formed from nylon, polyether block amide, PTFE(polytetrafluoroethylene), FEP (fluorinated ethylene propylene), PFA(perfluoroalkoxy alkane), PET (polyethylene terephthalate) or PEEK(polyether ether ketone).
 75. The catheter of claim 66, wherein at leasta portion of the continuous lumen is coated with a lining.
 76. Thecatheter of claim 75, wherein the lining is formed from nylon, polyetherblock amide, PTFE (polytetrafluoroethylene), FEP (fluorinated ethylenepropylene), PFA (perfluoroalkoxy alkane), PET (polyethyleneterephthalate) or PEEK (polyether ether ketone).
 77. The catheter ofclaim 66, wherein at least one edge of the connector and acceptor arebeveled at an angle ranging between about 5° to 90°.
 78. The catheter ofclaim 66, wherein the at least one stabilizing element prevents thefirst and second tubular modules from rotating with respect to eachother.
 79. The catheter of claim 66, wherein the diameter of thecontinuous lumen is maintained around a central luminal axis when thefirst or second tubular module form a curvilinear shape.
 80. Thecatheter of claim 66, wherein the at least one connector extends fromthe first tubular module and has the same wall thickness as the firsttubular module.
 81. The catheter of claim 66, wherein the tongue elementhas a rectangular shape.